Atomic emission spectrometer (AES) with inductively coupled plasma (ICP) provides the advantage over classical AES that solid pulverulent samples can be introduced into the plasma without the incorporation in the samples of possible chemical contaminants required in the earlier systems to solubilize or dispense the samples. Since solvents and chemicals required for preparing the samples can be eliminated and the expense and time consuming operations for sample preparation avoided, ICP-AES represents a significant advantage. It is also advantageous over classical AES that the reduction in sensitivity resulting from dilution of the sample is precluded as well.
In spite of these advantages, however, the use of a sample feed to the ICP plasma without dilution and contamination by chemicals used to process the sample has not found widespread application, since sample loss has not been possible to avoid in earlier systems A mechanical lifting of the sample containing crucible or graphite vessel is described in Applied Spectroscopy, Vol. 40, No. 3, 1986, pages 387 ff.
In this system, the sample-containing vessel, i.e. a graphite crucible, is lifted toward the plasma torch. The elevation of the crucible has been found, however, to disturb the plasma and there is also a danger of carbide formation from the plasma materials within the hot plasma from the carbon of the crucible. This can reduce the resolution of the system.
In a literature survey or report entitled "Thermal Vaporisation for Inductively Coupled Plasma Optical Emission Spectrometry" authored by Matusiewicz, June 1986, Vol. 1, the importance of the feed systems and the interface between the sample source and the plasma are discussed, although a satisfactory solution to the problems described has not been there taught.